Screw cap closure

ABSTRACT

A screw type cap for containers is provided which is adapted to engage the sealing edge or the top of the neck of a container. The cap is formed with an annular groove about the periphery of the central portion of the top. The groove opens downwardly to receive and sealingly engage the sealing edge of the container. An internal liner may be inserted in the cap to improve the seal particularly when the cap is to be used to seal bottles whose top sealing edge is not uniformly normal to the longitudinal axis of the neck. The liner engages the sealing edge and is deflected upwardly with the internal groove receiving the deflected portion of the liner and maintaining it in sealing engagement with the sealing edge.

United States Patent 11 1 Menkel Dec. 25, 1973 SCREW CAP CLOSURE [75] Inventor: Gary G. Menkel, Holliswood, NY.

[73] Assignee: Design Center, Inc., Long Island City, NY.

221 Filed: Dec. 17,1969 21 Appl. No.: 885,900

52 US. Cl 215743 a Primary ExaminerGeorge T. Hall 7 Attorney-Curtis, Morris and Safford 5 7 ABSTRACT A screw type cap for containers is provided which is adapted to engage the sealing edge or the top of the neck of a container. The cap is formed with an annular groove about the periphery of the central portion of the top. The groove opens downwardly to receive and sealingly engage the's'ealing edge of the container. An internal liner may be inserted in the cap to improve the seal particularly when the cap is to be used to seal bottles whose top sealing edge is not uniformly normal to the longitudinal axis of the neck. The liner engages the sealing edge and is deflected upwardly with the internal groove receiving the deflected portion of the liner and maintaining it in sealing engagement with the sealing edge.

9 Claims, 3 Drawing Figures PAIENIEDDECZS 197a 3.780.898

INVENTOR GARY G. MENKEL BY Mm b %.4

ATTORNEYS SCREW CAP CLOSURE The present invention relates to bottle closures, and particularly to a screw type cap capable of forming a fluid tight seal on its associated bottle top.

An inexpensive fluid tight screw type cap has long been sought in the bottling industry. Such caps as are presently available require the use of a rubber gasket, a fluid tight wrapping around the cap and bottle neck, or the crimping of the side wall of the cap against the bottle.

It is an object of this invention to provide a screw type cap which will afford afluid tight seal with the sealing edge of a container without the use of any additional elements or steps. It is a further object of the present invention to provide a screw type cap which, in conjunction with an internal cap liner, is capable of forming a fluid tight seal with a bottle having either an irregular sealing edge or one which is not uniformly normal to its longitudinal axis, such as found in plastic bottles. A still further object of this invention is to provide a screw type cap that is adapted to be thermoformed from a sheet of plastic material and which is adapted to receive an internal liner bearing indicia such as trademarks or advertising capable of being viewed through the cap.

In accordance with the preferred embodiment of the invention there is provided a screw type cap thermoformed from a sheet of plastic material. The cap includes a top and a cylindrical skirt having screw threads formed therein. The top of the cap has a downwardly opening annular groove formed on the periphery of its central portion. The groove includes an outer downwardly and outwardly sloping side wall joined to the cylindrical skirt and an inner downwardly and inwardly sloping wall joined to the substantially planar central portion of the top wall of the cap. When the cap is screwed on a bottle or the like, the groove receives the top sealing edge of the bottle and engages the top edge of the bottle to form a seal therewith. Due to the inherent flexibility of the material used to form the cap any irregularities in the bottles sealing edge will be accommodated by the local deformation of the cap and a fluid tight seal will be produced. A fluid impervious liner may be inserted in the cap and maintained there by interference fit, for bottles which have extreme edge irregularities or which have a sealing edge not uniformly normal to the longitudinal axis of the bottle. The peripheral edge portion of the liner will engage the bottle's sealing'edge as the cap is screwed on and will act as a gasket. That portion of the liner engaging the sealing edge will be deflected into the caps annular groove while the central portion of the cap top and the outer wall of the groove on the cap top act on the liner to maintain it in fluid tight sealing relation with the top sealing edge of the bottle. That portion of the liner that is engaged by, and adjacent to, the central portion of the top is available for the application of indicia such as trademarks or advertising which will be visible through the plastic material. 7

The construction of the preferred embodiment as well as the advantages thereof, which includes simplicity of design, economy of manufacture, and the provision of a fluid .tight seal for containers using screw type caps, will become further apparent from the following specification when considered in conjunction with the accompanying drawing wherein:

FIG. 1 is a fragmentary sectional view of the cap of this invention in direct sealing relation with a bottle;

FIG. 2 is a fragmentary sectional view of the cap of this invention wherein a liner is used to form the seal;

FIG. 3 is a perspective view of the cap illustrated in FIG. 2.

With reference to the drawings, and particularly FIG. 1, a cap 10 is shown in fluid tight sealing engagement with a portion of a container 12 having a cylindrical neck 14. An external screw thread 16 is provided on the neck 14 and the mouth of the bottle has a top sealing edge 18 which engages the cap 10.

The cap 10 includes a top wall 20, a cylindrical skirt 22 and a flange 23. The top wall 20 includes a generally flat circular central portion 24 and a raised groove 25 around the periphery thereof. The groove is defined by a generally flat annular surface 26 and walls 28,30. The central portion 24 is interconnected with the raised surface 26 by inner wall 28 which extends generally downwardly and inwardly from the inner edge of the surface 26 to the outer edge of the central portion 24 and skirt 22 is connected at its upper end to the surface 26 by wall 30 which extends downwardly and outwardly from the outer edge of surface 26 to the top edge of skirt 22.

The cap 10 and skirt 22 have an internal diameter greater than the externaldiameter of the bottle neck 14 and the skirt 22 is threaded internally as at 32 so as to be screw threaded in telescopic relation on the neck of bottle 14 in cooperation with threads 16. The outer annular wall 30 of cap 10 is provided with a plurality of lugs 34 about its periphery. These lugs enhance the structural stability of the relatively thin cap and provides a griping surface on the cap to facilitate threading it on or off the bottle.

The outer diameter of the annular flat surface 26'is preferably approximately equal to the outer diameter of the neck 14. Thus, when the cap 10 has been fully threaded on the neck of a bottle, the sealing edge 18 of the neck 14 will engage the under side of the surface 26 in groove 25 adjacent the junction 31 formed by surface 26 and wall 30. The engagement of the edge and the groove as illustrated in FIG. 1 forms a fluid tight seal between the bottle and the cap. The cap 10 is preferably thermoformed from a sheet of plastic material (polypropylene has been found suitable for this purpose although other plastics which may be formed while heated may also be used).

Due to the inherent flexibility of the material, any irregularities in the bottles sealing edge will be accommodated by local deformation of the cap and thus the fluid tight seal is assured. This deformation is facilitated by the fact that, as a result of the thermoforming process used to make the cap, the thinnest portion of the cap, and thus the portion most subject to local deformation, is adjacent the groove-25.

The use of a clear plastic to form the cap permits the insertion within the cap of a disk bearing indicia such as a trademark, which can be viewed through the cap as shown in FIG. 3. When so situated, the indicia is protected from accidental removal or destruction during shipment or in the normal course of handling and printing suitable indicia on the disk and avoids the difficulties associated with printing on plastic or applying a separate label to the cap.

When it is desired to use the cap 10 on a container, particularly a plastic bottle, which has an irregular sealing edge or a sealing edge which is not uniformly normal to the longitudinal axis of the bottle, a fluid impervious disk liner v36 may be inserted in the cap, as illustrated in FIG. 2, in order to effect the desired fluid tight seal. The liner has the same circular shape as the cap and a diameter slightly greater than the minimum diameter of the cap at the base of the threads 16. Thus, the liner has a slight interference fit in the cap but due to the flexibility of the cap and liner, the liner may be inserted in the cap with little or no distortion of the cap. Alternatively, the liner may be held in place by aninterference fit with a series of lugs projecting inwardly of the skirt 22 slightly below wall 30.

The liner 36 may be made of any relatively stiff fluidimpervious material capable of forming an effective seal, for example, conventional treated paperboard. The side of the liner adjacent the cap may also have indicia such as a trademark printed thereon.

As previously indicated, the outer diameter of the surface 26 is approximately equal to the outer diameter of the bottleneck 14. While the exact dimensions of the disk liner 36 relative to the cap are not critical, in the preferred embodiment, the diameter of the liner is larger than the outer diameter of the neck 14 so that the disk overlies the sealing edge 18 of the bottle with its-outer edge 38 in engagement with the inner surface of the inclined wall 30. As the cap is threaded'on the bottle neck, the under side of the liner 36 is seated on the sealing edge 18 inwardly of the concentric edge 38 and the central portion 20 of the cap bears against the top surface of liner 36. The junction 32 of the central portion 20 of the cap and the inclined wall 28 form a fulcrum on edge 40 that is substantially concentric with the line of contact between the edge 18 and disk 36 and the line of contact between the edge 38 and wall 30. When the cap is threaded on the neck to tighten it on the bottle, the sealing edge 18 is forced against-that portion of the liner'between the fulcrum 40 and the edge 38 of the disk 36. As the fulcrum 40 and central portion 24 of the cap bear down on the cap interiorly of the sealing edge 18, and the wall 30 bears down on the outer edge 38 of the disk exteriorly of the sealing edge 18, an upwardly concave bend or bow is imposed on that portion of the liner between fulcrum 40 and edge 38 against sealing edge 18. The edge 18 is in sealing engagement with the liner at all times after the liner is seated thereon. The force required to form the seal is a function of the stiffness of the liner, however, sealing is enhanced by the inclined wall 30 which, due to its slope, holds the edge 38 of the liner down against the upward thrust of the sealing edge 18 as the liner is bent and the lateral reach of the wall 30 is reduced. In this embodiment the groove serves not only in forming the seal but also to accommodate the upwardly bent portion of the liner. 1

While the cap and liner combination described above may be used with any type bottle neck it is particularly useful with bottles that have sealing edges which are not square or uniformly normal to the axis of the bottle neck. Since the liner effects a fluid tight seal at any level within the groove l2, it can accommodate a rangeof variations in the slope of the sealing edge 18.

Attention is directed to FIG. 2 wherein there is illustrated a bottle neck having a sealing edge 18 which is higher at the left side of the figure than at the right side tion of the sealing edge 18 is not forced into the groove but a fluid tight seal is maintained by the pressure applied to the liner by fulcrum 40 and wall 30. The view of the seal at the right side of FIG. 21 is illustrative of a minimum sealing engagement. The capacity of the liner 36 to bend upon tightening of the cap is designed to accommodate the range in variations between the high and low portions of the sealing edge 18 that may be encountered in a particular type of bottle.

When the liner is treated to make it fluid impervious, the selection of a material that may be softened when subjected to heat and that will adhere to the sealing edge 18 of the bottle 12 when it cools, will provide an improved seal. A liner treated with this type of material will remain fixed on the bottle when the cap is removed and must be separately removed to open the bottle.

it is thus seen that a screw type closure cap is provided which affords a simple and effective fluid tight seal on a container top by simply tightening the cap against the sealing edge of the container neck.

What is claimed is: v

l. A screw type cap adapted to be threaded onto the externally threaded neck of a container for forming a fluid tight seal with the container comprising;

a circular top wall and a generally cylindrical skirt depending from said top wall at the periphery thereof and having an internal screw thread formed thereon adapted to cooperate with the external screw threads on the neck of the container for securing the cap thereto,

said top wall including a substantially planar central portion and an annular groove formed on the periphery thereof,

said groove defined by a first outwardly sloping annular wall extending upwardly of said central portion and a second downwardly and outwardly sloping annular wall spaced outwardly from said first wall and joined to said skirt, said groove opening downwardly to receive the sealing edge of the container whereby upon tightening of said cap on the container the sealing edge of the container is engaged within the groove and forms a fluid tight seal therewith.

2. The screw cap as defined in claim 1 wherein;

said groove includes a flat annular surface upwardly of said central portion, said first annular wall extending downwardly and inwardly from the inner edge of said surface to the periphery of said central portion, and said second annular wall extending downwardly and outwardly from the outer edge of said surface to said skirt.

3. The screw type cap as defined in claim 2 wherein said second annular wall includes a plurality of annularly spaced projection means for providing a gripping surface to facilitate threading the cap on the bottle.

4. The screw type cap as defined in claim 1 wherein the cap is made from a thermoformable plastic material.

5. The screw type cap as defined in claim 4 wherein the plastic material is polypropylene.

6. A screw type cap for use as a fluid tight closure on the externally threaded neck of a container comprising;

a central substantially planar circular disk portion having upper and lower surfaces,

an annular groove formed on the periphery of said disk, extending above said upper surface and opening at said lower surface, and

a cylindrical skirt depending from the periphery of said groove and including an internal screw thread whereby said cap is threadably secured to the neck of the container.

7. The cap as definedin claim 6 wherein the neck of the container includes a sealing edge and said groove includes a flat annular surface above said upper surface and an outer inclined wall extending outwardly and downwardly from said surface to said skirt whereby upon the tightening of said cap on said neck the sealing edge of the neck is engaged with the flat annular surface of the groove adjacent its junction with the inclined wall to form a fluid tight seal. a

central portion. 

1. A screw type cap adapted to be threaded onto the externally threaded neck of a container for forming a fluid tight seal with the container comprising; a circular top wall and a generally cylindrical skirt depending from said top wall at the periphery thereof and having an internal screw thread formed thereon adapted to cooperate with the external screw threads on the neck of the container for securing the cap thereto, said top wall including a substantially planar central portion and an annular groove formed on the periphery thereof, said groove defined by a first outwardly sloping annular wall extending upwardly of said central portion and a second downwardly and outwardly sloping annular wall spaced outwardly from said first wall and joined to said skirt, said groove opening downwardly to receive the sealing edge of the container whereby upon tightening of said cap on the container the sealing edge of the container is engaged within the groove and forms a fluid tight seal therewith.
 2. The screw cap as defined in claim 1 wherein; said groove includes a flat annular surface upwardly of said central portion, said first annular wall extending downwardly and inwardly from the inner edge of said surface to the periphery of said central portion, and said second annular wall extending downwardly and outwardly from the outer edge of said surface to said skirt.
 3. The screw type cap as defined in claim 2 wherein said second annular wall includes a plurality of annularly spaced projection means for providing a gripping surface to facilitate threading the cap on the bottle.
 4. The screw type cap as defined in claim 1 wherein the cap is made from a thermoformable plastic material.
 5. The screw type cap as defined in claim 4 wherein the plastic material is polypropylene.
 6. A screw type cap for use as a fluid tight closure on the externally threaded neck of a container comprising; a central substantially planar circular disk portion having upper and lower surfaces, an annular groove formed on the periphery of said disk, extending above said upper surface and opening at said lower surface, and a cylindrical skirt depending from the periphery of said groove and including an internal screw thread whereby said cap is threadably secured to the neck of the container.
 7. The cap as defined in claim 6 wherein the neck of the container includes a sealing edge and said groove includes a flat annular surface above said upper surface and an outer inclined wall extending outwardly and downwardly from said surface to said skirt whereby upon the tightening of said cap on said neck the sealing edge of the neck is engaged with the flat annular surface of the groove adjacent its junction with the inclined wall to form a fluid tight seal.
 8. The cap as defined in claim 7 wherein said cap is formed of a flexible plastic material whereby local deformation of the groove on the sealing edge provides a fluid tight seal against edge irregularities on the sealing edge of said container.
 9. The cap as defined in claim 8 wherein said plastic material is clear polypropylene and a disc-like liner provided with indicia is interference fitted within said cap adjacent the lower surface of said central portion whereby the indicia on said liner is visible through said central portion. 